I believe weight is the difference. I think Eibach makes a set that is the same size bar as stock, but they are hollow making them lighter. So basically, if you already have the stock bars on the car they should be more than sufficient, unless you want a lighter weight set.
Haha, for drag racing only, and even then, only the front bar. Driving a no-sway bar car on the street makes the car feel like an old jeep with all the body roll. A lot of people like to pop off the front bar before a day at the track, and then put it back on for street driving.
Mechanically, torsional stress/strain relies more on tube diameter than it does cross sectional area. In other words, hollow sway bars can actually be more rigid than solid sway bars, given that the diameter of the hollow bar is large enough.
That said, like someone stated above, the stock front sway bars are typically considered more than stiff enough, but hollow aftermarket sway bars can help with weight savings. In some high power drag racing applications adjustable, high strength rear sway bars are used to keep the car level on launch, particularly for cars that lift the front wheels.
Thanks guys! My buddy told me the difference! Hollow are more likely to crack road racing which is what i want to do a little bit. He said i could go smaller it i went with a solid one. Don't get me wrong I LOVE DRAG RACING! But I would like the best of but worlds if possible.
MY old 97 Cobra had no sway bar for a couple weeks and I drove it around and I didn't feel much of a difference when I installed it. I didn't take it on crazy fast turns, just normal street driving. I thought it would be night and day and it wasn't.